Tengukan-Ryu-Ninjutsu is based off of Timothy Andersons findings years ago when he discovered through History of "A Religious Study of The Mount Haguro Sect of Shugendo by, H. Byron Earhart (1970.)" a Ninjutsu Connection through the "Haguro Shugendo-Sect's Yambushi Martial-Arts:"Tengu-Sumo."
Ref:"Shura:the practice of Sumo*(wrestling) or Tengu-Sumo,pg.132 also, H. Byron Earhart A Relgious Study of The Mount Haguro Shugendo-Sect (1970.)